As a kind of novel carbon material of a two-dimensional plane structure, graphene, due to its excellent electron transmission performance, high specific surface area and ultrahigh thermal conductivity and electrical conductivity, has many potential applications in the fields such as super capacitor materials, liquid crystal devices, electro-catalysts and sensors.
The common preparation methods of graphene include: mechanical exfoliation, vapor deposition, exfoliation of graphite oxide by (electrical) chemical reduction, exfoliation of graphite oxide by high-temperature expansion, etc. The exfoliation of graphite oxide by high-temperature expansion is mostly likely to be used in the mass production of graphene. However, the exfoliation of oxide graphite by expansion has a starting temperature over 550° C. and is generally performed in an inert atmosphere or in vacuum at 900-1100° C., resulting in severe conditions and high energy consumption. Recently, some researchers have realized the low-temperature exfoliation of graphite oxide in high vacuum. However, as the exfoliation of oxide graphite by expansion is a process in which a large amount of gas will be generated, realizing a high degree of vacuum becomes more difficult. Hence, this method is unsuitable for the mass production of graphene. In addition, with regard to the preparation of graphene by using graphite oxide as raw material, it is still difficult to prepare the graphite oxide itself.
It can be seen that the existing graphene preparation technologies or processes are complicated, or require expensive reductants or too high temperature, or has high energy consumption or even explosion risks, or the like. The preparation methods of graphene-based composite material developed on the basis of the existing graphene preparation technologies has the similar difficulties. Therefore, it is necessary to further develop preparation technologies of graphene and graphene-based composite material, which are low in cost and suitable for mass production.